102 
LIFE, IN ITS LOWER FORMS. 
own roward. From each of the avenues hundreds of 
filmy tubes are seen protruding, which twist and twine in 
all directions, as if seeking some object to lay hold of. 
Nor do they seek in vain. We are supposing that the 
Star-fish has been laid upon his back. Well, the extre- 
mity of one of his rays presently bends itself over, so that 
the pellucid tubes can reach the bottom ; — they catch 
hold ; the arm bends still more ; other tubes reach the 
ground, and, in a minute or two, over turns the Star-fish 
bodily, and is “ as right as a trivet.” 
See how gently and equably he is crawling over the 
bottom, gliding uniformly along like a snail ! But how 
does he do it 1 What is the nature of his locomotion ? 
Stay ! we shall see ; for he has reached the edge of his 
prison-bottom, and is beginning to mount up the glassy 
side. Watch him now, through the transparent medium, 
and you will understand the secret. 
The flexible tubes, which look like so many caterpillars, 
are seen to have dilated extremities, which, w'hen brought 
into contact with the glass, are made to adhere, just on 
the same principle as a truant schoolboy makes his 
sucker of wetted leather stick fast to the pavement. The 
tubes are thrust out and drawn in at pleasure ; as the 
Star-fish advances, new sucker-feet are pushed onward as 
far as possible, where they adhere, and drag up the body 
after them ; and by a succession of such apparently feeble 
efforts progression is effected. 
The mechanism of these suckcr-feet is very simple. At 
the bottom of the furrow or avenue in each ray are four 
rows of minute pores, through which the suckers are pro- 
truded. Tho base of each sucker is expanded into a little 
